The invention is directed to an apparatus for the interior coating of cavities, particularly of an automobile body, comprising a spray gun having a spray nozzle plug-in coupling and a spray shot trigger means and comprising nozzle probes pluggable to the spray gun, each nozzle probe being composed of a nozzle tube having a plug-in end, nozzle end and positioning detent.
Such an apparatus is disclosed by EP 140 017. In the disclosed apparatus, spray probes are detachably secured to a spray gun. The spray probes are stored in a holder part having a plurality of receptacles and are taken as needed by the worker and secured on the spray gun. Every receptacle in the spray probe holder has a holder as well as a display lamp allocated to it, this lamp being respectively lit when the corresponding spray probe has been removed from the holder. In addition, a symbol display panel having small lamps likewise allocated thereto is present, this being connected with lines to the spray probe holder and to a control means and the respective spraying position of the corresponding spray probe being displayed thereon, whereby the small lamps are respectively lit as the corresponding lamp at the spray probe holder lights up given removal of the spray probe. On the basis of the worker's attention, it is thus assured with the system that the correct spray probe is introduced into the correct cavity. Measures for assuring that the spray probe is correctly introduced into the cavity with respect to direction and depth (exact seating of the positioning detent against the wall of the cavity surrounding the introduction opening), however, are not provided in the known apparatus. The same is also true of the procedure of correctly fastening the spray probe to the spray gun.